(CNN) -- A woman who was convicted at a trial for wearing pants -- clothing deemed indecent by Sudanese authorities -- was released from jail Tuesday after being imprisoned for a day, a United Nations spokesman said.

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Al-Hussein, who was arrested in July, pleaded not guilty during her one-day trial, Adib said. She was not allowed to call defense witnesses or present a defense case, he added.

"She thinks that she did not have fair trial and a conviction was wrong so she did not want to pay the fine nor let anyone else pay on her behalf," Adib said.

Al-Hussein resigned from her U.N. position to waive her immunity as an international worker and face trial.

U.N. Secretary-General Ban Ki-moon said he is concerned about al-Hussein's case.

"The United Nations will make every effort to ensure that the rights of its staff members are protected," Ban said in July. "The flogging is against the international human rights standards."

In August, scores of protesters supporting al-Hussein gathered outside the courtroom in Khartoum, waving banners and wearing headbands with the messages, "No return to the dark ages" and "No to suppressing women."

On Monday, Sudanese security forces fought back scores of al-Hussein supporters, injuring some and detaining 47 women, according to an eyewitness who spoke to CNN by phone.

A Sudanese official accused "the West" of interfering in the case.

Al-Hussein was arrested along with 18 other women on July 3 at a Khartoum restaurant when police burst in and checked women for their clothing. At the time of her arrest she was wearing pants, a blouse and a hijab -- a headscarf worn by Muslim women, she said.